86
length of time a mitogen solution was stored at 4C. Responses to PHA
or Con A were always significantly greater (p < 0.01) than responses to
LPS, PIVM, or PPD, with stimulation indices of PHA or Con A ranging from
40-250 and those for LPS, PWM,or PPD stimulated cultures between 1-25.
Assay for In Vitro Cellular Reactions
To determine if TCA precipitable counts were a valid measure of
cellular events in culture, the number of labeled cells stimulated
with various concentrations of LPS or PHA were correlated with the
Y
TCA precipitable counts in experiments (Chapter II). The results are
presented in Figures 11 and 12 and indicate that both LPS-and PHA-stim-
ulated cultures exhibit changes in TCA precipitable counts closely
paralleling those changes in percent of labeled cells identified by
autoradiography. Cells optimally stimulated with PHA (1 yl) were pre
dominately in aggregates and looked like lymphoblasts (Figures 13a and
13b). Cells optimally stimulated with LPS (10 yg) were also morphologi
cally characterized as blast-like but were not clumped (Figures 14a and
14b).
Comparison of Peripheral Blood and Splenic Lymphocyte Mitogen Responses
To assay whether mitogenic responses of peripheral blood lympho
cytes were similar to the mitogenic responses of lymphocytes from other
sources, cell suspensions were prepared from various alligator lymphoid
tissues. Only the spleen cell suspension yielded a sufficient number
of lymphocytes (isolated by Hypaque-Ficoll) to culture in a mitogen
assay. The results obtained from mitogenic stimulations of peripheral
blood and splenic lymphocytes are presented in Table 17. Optimal dose
and time responses of both isolated lymphocyte populations were the same